Fluid-operated power system



1952 E. M. GREER ETAL 2,583,295

' FLUID-OPERATED POWER SYSTEM Filed June 14, 1944 2 SHEETS-SHEET 1 IN VEN TORS Jean filerca'er BY Edward M 611 5:?

ATTORNEYS 22, 1952 E. M. GREER ETAL 7 2,583,295

FLUID-OPERATED POWER SYSTEM Filed June 14, 1944 2 SHEETS-SHEET 2 #FH .15zfl laa fi m 5 1/ 1 20 V/ 4/ 4 Al 1 4 I INVEZVTORS Jean Merger and. BYEdward M fiREEfi' Wad/(r 4M HTTORNEYS Patented Jan. 22, 1952FLUID-OPERATED PQWERQSYSTEM Edward M. Greer, West Hempstead, and JeanMercier, New York,.N.Y.'; said :Greer-assignor -to-said MercierApplication'June 14, 1944, Serial No. 540,276

2 Claims. (01. 137-453) Our invention relates'to-a new and improvedmethodof and means for controlling the flow of fluid in'a fluid-operatedpower-system. The'zfluid may be a liquid ora gas. If the fluid isva gas,the system can operate the motor-device or motor-devices by compressedgas, orit 'can be 'a vacuum-power system.

Without restricting the scopeof the invention, it relates particularly:to the-controlsof the motive fluid in fluid-operated power :systems.which are used in airplanes,'for.operating turretsalanding gear, andother-parts.

In such systems, a forward Fflow o! "fluid is produced through theentire. pipe line and through the motor'device by apump from any source..0! pressure or "vacuum. The pump or other: source of pressureoryacuumis .connectedito the cylinder or other'motor-device, by amineline. Thereis usually a'return pipe-line from the motor device to thepump or to the'sourceof pressure :or

vacuum.

The entire pipe system :and the motor-device may be filled with themotive *liquidor other motive fluid.

Due to wear or-accidents or enemyfirehthe pipe line is frequentlysubjectedto leakagaand said pipe line may be. destroyed.

In such systems, even if the masteryalve is closed, and the entiresystem. is ,in-perfectworking condition, there may be-a slow internalsteakage how of the motiveliquid-or other motive fluid through the-system,dne to leakage between the master valve andv its-valve-seat,leakage hetween the piston and: cylinder of themotor-de vice,- etc. Thesystem .may he designed .sothat such internal leakagedflow'its-"negligible, or the system may bedesigned toahave a slow internalintermittently. ln-suchicase, theperiodofopera-- tic-n of such.jilfiflt, such as. thelandinggear, requires a predetermined period ofoperation; :plus an additional safety-period. Insuch case, we use acontrol unit .in which. the .fiow ofmotive fluid is stopped after:the:mo.tiv.e::liquid ,hasrflowed through the-control period .atsavelocity which exceeds "the internal leakage velocity, plus the safetyperiod. This does not depend upon the velocity of the flowing liquid, aslong as said velocity exceeds the velocity of internal leakage flow.

In another case, as in operating the turret of an airplane, which mustbe operatedcontinuously during long periods, the controlunit is operatedto stop the flow of motive fluid-after the master valve has been opened,after the motive fluid has flowed through the control unit at more thannormal operating velocity, during a predetermined period.

Numerous additional objects and advantages of my invention will bestated inthe annexed description and drawings, which illustratepreferred embodiments thereof.

Fig. 1 is a longitudinal cross-section ofa control unit made. accordingto our invention. This unit stops the how of motive fluid to themotordevice, at the end of a predetermined delay period, during whichthe flowof the motive fluid exceeds normal operating velocity. Thisdelay period may be of any desired length.

,For example, the control unit of Fig.1 may be used to operate theturretof an airplane, or other device which must be continuouslyoperated durme a long period of time. When the master valve is opened,and-the power sy -ism norma working conditio the motive liquid will flowat normal operating velocity. The control unit of Fig. .1 wil stop theflow of motive fluid. 9 15 aftera predetermined delay period duringwhich the motive. fluid has flowed through the contro1 unit at morethannormal. operating velocity.

Fig. 2 is alongitudinal cross-section of .a second embodiment, whichoperates in the same manner as Fig. 1.

Fig. 3 is a longitudinal sectional view of a. third embodiment, whichincludes an auxiliary valve 2 1 In this embodiment, the control unitwill shut off the flow-of motive fluid, at the end of a predetermineddelay periodv after the master valve has beenopened, irrespective of thevelocity of flow of the motive fluid during said delay period. Hence, inthe embodiment of Fig. 3, after the motive fiuid has ilowedthrough' thecontrol during a predetermined period, even at :normal operatingvelocity. the additional flow .of motive fluid will be stopped; if the:master ;val.ve remains open.

Hence, the embodiment of Fig. dis-especially adapted for operating thelanding-gear of anairplane, for example. If it requiresthree seconds tooperate :said landing-gear, as an example, plus 3 a safety period of onesecond, the control unit of Fig. 3 will stop the flow of motive fluid,after said fluid has flowed through the control unit during a period offour seconds, at more than internal leakage velocity.

Fig. 4 is a longitudinal sectional view of a fourth embodiment, whichoperates on the same principle as the embodiment of Fig. 3.

Fig. 1 shows pipes I and 2. which are part of the pipe-line between thesource of power and the motor-device. The source of power and themotor-device are not shown in the drawings, because they are well-knownper se. The fluid enters pipe 2 at inlet zone A, and it passes out ofpipe I at outlet zone B. The master valve, not shown, may be located inany part of the pipe line. It may be anterior zone A, or it may succeedzone B.

Pipes I and 2 are connected by cooperating threads, and a gasket 3provides a fluid-tight joint.

Hollow valve-body 32 has a cylindrical pistonhead 30, which fitsfluid-tight and slidably against the interior cylindrical wall of pipeI. Said piston-head 30 can have conventional piston-rings of the type ofthe ring 52 which is shown in Fig. 2. Pipe I has an inner cylindricalrib Ia, against which the cylindrical valve-body 32 fits fluidtight andslidably. The valve-body 32 may have said piston rings adjacent rib Ia.

Valve-body 32 has a valve-head 33, which can fit fiuid -tight against apart of the valve-seat 34a of pipe I. In this design, valve-head 33 hasline contact against valve-seat 34a.

Valve-body 32 is hollow and it has a narrow transverse bore 34, whichextends through the constricted wall-part 33a of the hollow valvebody32.

The piston-head 30 and the rib Ia, define a checking space orchecking-chamber S, which is filled with the respective fluid, when theparts are in the normal open operating position of Fig. 1. This fluid isthe same as the motive fluid. Said motive fluid may be of any type, suchas a gas or oil or other liquid. In said normal open operating position,motive fluid which flows out of outlet zone B, is supplied to themotor-device when the master valve is open. The mass of fluid which islocated in. the checking-chamber S, under said condition of normaloperation, is designated as the checking-fluid. Said checkingchamber Sis enclosed save for its outlet port 34, save that we may provide asmall leakage at rib Ia, where the piston-body 32 has a slide fit.

This leakage should be very small. The rear wall of saidchecking-chamber S is the front transverse annular wall of thepiston-head 39. Said chamber S is of continuous and equal annularcross-section.

A compression spring 3I is located in checkingchamber S. Said spring 3|rearwardly biases the valve-body 32, against the forward force which isexerted upon the valve-body 32, by the pressure head of theforwardly-flowing motive fluid.

When the fluid flows at predetermined normal operat ng velocity when themaster valve is open, the opposed biasing force of spring 3| exceeds theforce of the pressure of the fluid head, so that valve-head 33 ismaintained in the normal open operating position which is shown inFig. 1. When the forward flow of motive flu d is stopped by closing themaster valve,- valve-body 32 may be held against rearward movement fromsaid normal open position by a suitable stop, or valvebody 32 may thenbe moved rearwardly by spring 3i, until piston head 30 abuts pipe 2.Spring 3I may be under suitable initia1 compression.

Valve-body 32 is provided with a port P, which is located longitudinallyintermediate rib I a and valve-seat 34a, when valve-body 32 is in theOpen position of Fig. 1. There may be a plurality of ports P. As anexample, there may be three ports P.

Under normal operating conditions, when the master valve anterior zone Ais opened in the power system, and if the power system is a compressionsystem, the motive fluid flows at normal velocity through pipe 2, intohollow valve-body 32 at its open front end, through port or ports P. andout of zone B of pipe I, to the cylinder or other motor-device. Thevelocity of flow of the fluid, under such normal operating conditions,is less than a predetermined maximum.

At normal operating predetermined flow velocity, the forward force ofthe pressure-head of the forwardly flowing fluid cannot move thevalvebody 32 against the force of spring 3|, to the right, namely,forwardly of the normal open operating position which is shown in Fig.1.

When the forward flow of the fluid towards zone B exceeds said normalmaximum velocity, the forward force of the pressure-head of the flow ngliquid exceeds the opposed force of the biasing spring 3I, and thevalve-head 33 will be moved to closing position, at the end of apredetermined closing period, during which checkingfluid is aspiratedout of the checking-chamber S, through port 34.

When the valve-body 32 has been moved from the normal operating positionto its clo ing position, in which the valve-head 33 of valve-body 32abuts valve-seat 34a, at least part of the mass of checking fluid whichinitially fills chamber S, when said chamber S has the normal volumeshown in Fig. 1, will have been removed from chamber S. The length ofthe clos ng period is thus regulated by the rate at which thecheckingfluid is removed from chamber S when the velocity exceeds normalvelocitv, either by aspiration or pressure or both. The biasing force ofspring 3| may vary only very slightly, or to anv de ir d ext nt, duringthe closing movement of valve-body 32.

Hence if the embodiment of Fig. 1 is used for controlling the flow ofmotive fluid for operating a motor-device for actuating a turret, forexamp e, valve-head 33 will remain spaced from valve-seat 34c as long asthe power system is in normal working order. If the power system whichis located after zone B leaks for any reason, and the master valve isopen, the motive fluid will flow throu h the control unit at more thannormal operating velocity. After a predetermined delay period. which maybe very short or of any desired length, under said condition ofexcessive ve ocity. va ve-head 33 will be moved. against valve seat 34a.and the pressure of the fluid in zone A and in the control unit willstop the flow of motive fluid. through the control unit, until the leakis repaired.

Fig. 2 shows a modified hollow valve-body 40. The p pe 1 has a taperedvalve-seat 5|, instead of the non-tapered valve-seat 34a. The pipe I isprovided with an integral extension 4|, which has an inner cylindricalwall against which valvebody '48 fits sli'dably and fluid-tight. Saidextension iI has a narrow bore 42.

A nipple N has a shank which is threaded into a tapped bore of pipe I.Said shank has an inner recess 44. The wall of the shank is per-.

essence predeterminedtnormal operating velocity when .the Imaster "valveis opened, :the pressure-head of the motive fluidsmoves valve-body cc,lforwardly out of itsxnorma'l open operating position which iS'ShOWD'LiIl Fig. 2," thus :torcing the. :checkingfluid out-cf thechecking-chamber S .at a regulated rate, through-passage =43, recess 34and bore 42. As :in Fig; 1, the period of delay in stoppingfthe .flow ofliquid is -.determined' substantially .by the rate at which thechecking- Iiuid 'is removed from chamber .8. The length of the closingmovement of valve-body 4: 3 -may be short, so that the opposing force ofspring 3| may remain -.substantial ly constant during the closingmovement, as .in the embodiment of 1. This is optional, because thecounter force of springa'lmay :increase as desired, during the closingmovement. Preferably, only part of the mass of checking-fluid :is forcedout ofiacha-m- Mr S, during the closing movement, in each embodimentdisclosed herein.

Fig. 3 :shows the pipe provided with-a hol low and longitudinally'sl'idable valve-body ii,

which has a piston-head so. This embodiment has the checking-chamber orspace S, and a compression spring-3i, as in the previous embodiments.Valve-body 1'! has ports 18, and .a valve-head l8,- and pipe i has avalve-seat 2E2.

A nut 24 is threaded into one end of valve- .hody 11.. .An auxiliaryvalve 2i, which has :a port .22; fits slidelbly, and .eitherfluid-tighter nonefiuid-tight, against the inner cylindrical wallof-varlve-body l1. .An'iauxiliary spring. rea=rwardlv biases auxiliaryvalve 24 :so that its rear or left-hand-valve-wall :normally abuts therespective transverse wallcf Illhle nut at, which serves as avalve-seat.

fIhe valve-body H has a narrow bore lea.

Fig. 3 shows the positions of the parts, when the control-valve anteriorzone .Ais closed, so that no fiuid is being forced towards zone 'A, savefor the slow internal lealgage flow, it any.

When the system is thus out-of o eration, pistonhead .33 may abut asuitable stop, such as the corresponding .end of pipe 2, so that spring131 mayiloe under. initial compression, when no motive fluid is flowing.

In this .enibodimentthe velocity of the motive fluid at which the flowor said motive fluid is stopped 'by the control unit, may besmall, or.it may'diifer only slightly from normaloperating velocity, orlr'rcminternal lealrageflow. That is, the control-unit of Fig. .3 isresponsive to, small leakages, so that Ii't will operate when the flowo'f'themotive fluid slightly exceeds arelative1y low maximum velocity.This .maximum velocity may "be the internal leakage velocity.

'In'FigS, .assoon asithe velocity of flow exceeds the .lownormalvelocity which results from internal leakagethroughrthe systen'rfluid isforced out of space S, through bore 13a, because the forward pressure ofthe fluid .now exceeds the resistanoeof-spring 3.! Hence, there isaemetered flow of checking-fluid out ofspacels,=.the rate of flow bei-ngcontrolled bythe diameter :ofhore 18a. At the, end of; ,a predetermined:period nfidel-31X! which is inversely proportionedto the elocityz iofflow above the leakage fiowwhichxis thertime ;re quired to operate, therespectiveedevice'ipluswa safety period, the valve head If] is forcedandheld against valve-seat thus; stopping therlfiowzof motivefluid..In-each embodiment, when thence mal velocity is exceeded the pressure-orzothe motive fluid keeps the respective valve -in closin position.

Fig. 4 operates for the :sameipurpose and on the same principle asFig.6.. I

In Fig. 4, the pipe I has :a valve-body sly-which hasga :pistonr'headdo. A sleeve Btis fixed to the inner wall of valve-body 4. Therauxiliaryvalve H is biased. by compression-spring :2, against the valve-seat ofsleeve Fig. elzshowsitheiparts, wihenmo :fiuidjs fiowinthrough thecontrol-unit, because the control valve which is anterior none-his'iclosed. .Asprevicusly noted, spring .31 maybe under. initialcompression, whenthe parts-rare in the respective positions-of Fig.4,3116. the valvebody 4 may be stopped from moving rearwardly of itsposition shownin Fig. 4. 'l/Talveebodyhmas a port .or ports il 0,andi'txa'lso has a relief leakagebore Illa. Valve-body ihasavalve-headll, which has a valve-surface ii 6:, whichcanabut *valveeseat#5.

When motive fluidtris forced :at normal leperating velocity in thedirectionaof arrow 4:41 :into and through zone -A and throughthesucceeding zone B, the valve I I is moved away. from its valve-seat,:so .that'the 'fiuid icanrflow through port :or ports is and throughthezspacenbetwcen valve-head 9 and valve-seat l5,iintozand' through zoneB. "This is the same as .the'zacti'on iof valve 2.1 of Fig. .3.

"The pipe [is provided atits .rib in, with :aiseries of finsfi. "Thevalve-body =4 has .a series of fins 6a. These fins define a narrow:labyrinth orxzigzagaouitlet .for the fluid, out of space S. :IIheoutlet end or this :labyrinth' is the narrow :bore fl.

When the velocity of :the motive .iluidiexcceds the predetermined.internal leakage velocity, the pressure of the; motive fluid-urges.valve 4 for wardly until its valve-head's abuts valveeseat A5. Thechecking-fluid isxforced out of space s at a regulated metered rate, 'sothat the 'nnitis closed. by valve-head :9, at :the end ofthe'zpredetermined period plus-ma, safety period. The control-unitristhus closed, after a predetermined volume of liquid has flowed throughsaid controlunit 'at more than the internal ,ll'eakage velocity. Thismaximum operating velocity canhe as email as is desired.

,Inxthe embodiments of :Figs. :3 and 4, thevcompression-zspringsx zt and4&2 'pl'OdllCBTIESIJfiCfi-MB constant differencesabetween the respectivepressure-heads of the :motive fiuid inazones A and B, so that thepressure .head of the flowing liquid "is greater in zone A than in rzone:B, by a'fixed amount, which 'is theoretically independent, of thevelocity of flow.

There is substantially a "stream-line flow ebe tween valve-head I B andvalve-seat 17.0, and also between'valve-head 9 and valve-seat 1! 5=withlittle or no turbulence, in :the designs illustrated in Fi s. ar1d Suchdesign canbe changed, in order to provide *for any desireddeparture-from stream-line flow at lit-26 and 9--l-5,with acorresponding increase in turbulence and pressure-head in the spacebetween the valve-head and the valve-seat.

At the inlet end of the hollow-valve-body I! or 4, there is a departurefrom stream-line flow, due to nut 24 and sleeve 8. This produces aturbulence and a loss of velocity-head at the inlet end of valve-body Il or 4, with a corresponding increase in pressure-head of the motivefluid.

Hence, if the motor-cylinder is broken behind its piston, this causes aleak and an increase in velocity of flow of the motive fluid and theresultant turbulence will result in an increase of pressure-head whichwill exert the necessary closing force upon valve-body I! or 4. The sameresult is secured if there is a leak in zone B, anterior the motorcylinder.

Hence, in the embodiments of Figs. 3 and 4, there are four factors whichregulate the period of closing of valve-head IE3 or valve-head 9,namely, the force of spring 23 or l2; the force of spring 3|; the timerequired to remove enough checking-fluid to permit the valve ll or 4 toclose; and the increase in pressure head of the motive fluid which isproduced by turbulence in the flowing liquid, with consequent reductionin velocity head.

This turbulence effect is an important advantage, because it minimizesthe leakage of fluid out of the system when the line is broken.

By producing turbulence between valve-head l9 and seat 20, or betweenvalve-head 9 and seat [5, which can be done by departing fromstream-line flow, the period for removing enough fluid from space S, topermit the closing of the valve H or 4, can be decreased. That is, byproducing turbulence at l920 or 9-l5, such turbulence is also producedat the outlet of space S. This increases the effective difference ofpressure head of the motive fluid between zone A and zone B, so that theincreased pressure head of said motive fluid in zone A will move thevalve-body forwardly with greater force, to force the checking-fluidmore rapidly out of space S, thus diminishing the period of delay inclosing the valve proportionately to the rate of flow in excess ofleakage flow.

In a vacuum system, the suction is applied at zone B, and thepower-cylinder or other motordevice is connected to zone A.

Considering Fig. 1, for example, when used in a vacuum system, thespring SI and the pressure of the checking air in checking space S willprevent valve 33 from c1osing, un1ess the velocity of motive air orother motive gas through the unit, exceeds a predetermined operatingvelocity. When the velocity exceeds said maximum operating velocity, theair pressure in space S will decrease at a metered rate, so that thevalve of the control-unit will be closed, after a predetermined periodof delay. This applies to the other embodiments, so that thecontrol-unit can be used for vacuum-brakes, for operating fans and otherrotors by the flow of air through the system, and the like.

In each embodiment, irrespective of other details, the pressure head ofthe flowing motive fluid urges a closure valve to its closing position,against a biasing counter-force. Said biasing counter-force keeps theclosure valve in open position, until the velocity of the motive fluidexceeds a predetermined maximum velocity. This maximum velocity may bean operating velocity or an internal leakage velocity. In eachembodiment, the period of delay in closin the closure valve is regulatedby the period which is required to remove a corresponding mass ofchecking- 8 fluid from a checking-chamber. The pressure of thechecking-fluid exerts an additional counterforce.

We have disclosed preferred embodiments of our invention, but numerouschanges and omissions and additions can be made without departing fromits scope.

We prefer to use a biasing spring or springs or other resilient ornon-resilient biasing means, whose force remains substantially constantor constant during the movement of the closing valve to closingposition, so that the period of closing is determined by the rate atwhich checking-fluid is removed from the checking-chamber, and said rateof removal, either by aspiration or pressure, remains constant duringsaid closing movement. It is well-known to provide a soft spring, whoseforce remains substantially constant, if the spring is slightly deformedfrom a predetermined shape or dimension. The drawings are diagrammaticand not to scale, and the length of spring 3| may greatly exceed thedistance of the closing movement of the closing valve, so that thespring is deformed only slightly during the closing movement.

The valve-head t can be of any shape. It can be of convex shape, as theshape of a part of a sphere.

As an example, when the flow through the embodiment of Fig. 4 is lessthan 0.1 gallon per minute, which is normal internal leakage flow, thevalve 9 does not move out of the open position shown in Fig. 4.

When the liquid flows at a rate between 0.5-5.0 gallons per minute, theshut-off occurs after a total volume of 0.5 gallon has flowed throughthe control device, with a variation of plus or minus 10%. If the motiveliquid is an oil, the amount of oil which flows through the system, upto the instant of shut-off, is affected only slightly if the viscosityof the oil is changed by a difference in temperature. This is animportant advantage in using oils or other liquids, whose viscositydepends on temperature. The reason is that since the checking liquid isthe same as the motive liquid, a change in viscosity will simultaneouslyaifect the flow of the liquid through the control device and out of thechecking-chamber. Since the liquid flows forwardly in the direction ofthe respective arrows, the solid closing heads 33, I9, and 9 are locatedat the front ends of the respec-- tive closing-valves.

We claim:

1. In a pipe-line of a fluid-operated power system through which fluidis forced longitudinally forwardly, the combination of a pipe-memberwhich has an internal valve-seat, a hollow valvebody which has alongitudinal axis and which is located in said pipe-member rearwardly ofsaid valve seat, said valve-body being open at its rear end and having avalve-head at, its front end, said valve-head having an imperforatvalve-surface which closes said pipe-member when said valvebody is inthe closing position, said pipe-member having an internal rib rearwardlyof said valve head and valve-seat, said valve-body fitting slidably insaid internal rib, said valve-body having a laterally enlarged pistonhead rearwardly of said rib, said piston head fitting against theinternal longitudinal wall of said pipe member, the space between saidpiston head and said rib and said valve-body providing achecking-chamber, said checking-chamber having only a lateral outletport which connects said checking chamber directly to the interior ofsaid hollow valve body,-

said valve-body having a lateral outlet port which is located rearwardlyof said valve-head, said outlet port being lateral relative to saidlongitudinal axis, said lateral outlet port of said valvebody beinglocated forwardly of said rib when said valve-body is in theopeningposition, biasing means which bias said valve-body to a rearopening position in which said imperforate valve surface is spacedrearwardly of said valve-seat, said biasing meansbeing suflicientlystrong to keep said valve-body in said opening position when thevelocity of flow of said fluid is at or below a predetermined normaloperating velocity, the force of said biasing means being insufiicientto keep said valve-body in said opening position when said velocityexceeds said normal velocity, said valve-head and the inner wall of saidpipemember at said internal valve-seat being shaped to provide a passagewhen said valve-body is in said opening position, said passageconverging towards said longitudinal axis, said outlet port of saidchecking-chamber being located only in said rib.

2. A combination according to claim 1, in

which said hollow valve-body has an internal 25 valve-seat, said hollowvalve-body having an internal valve which is biased rearwardly towardssaid internal valve-seat, said internal valve stopping the entry offluid into said hollow valve-body through its open rear end when saidinternal valve abuts said internal valve-seat, said internal valveobstructing the outlet port of said valvebody when said internal valveabuts said internal valve seat, said valve-head having a relief borewhich is spaced from said imperforate valve surface.

EDWARD M. GREER.

JEAN MERCIER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

